On 04/10/2019 01:52, nd...@redhazel.co.uk wrote:
On 04/10/2019 00:26, Dave F via Talk-GB wrote:
I think you're missing the point. Most contributors believe postcodes
on buildings or property nodes, add quality to the OSM's database,
but object to the import of codepoint as it's just not accurate
enough as stated in this, & numerous other threads.
This is incorrect. CPO/ONSPD postcodes _are_ accurate, up to date and
include all postcodes in the UK except NI.
Please note: "not accurate *enough*"
They are not complete (contain one and only one delivery point per
postcode),
No. The centre point is not associated with *any* delivery point. It is
an arbitrary mean, calculated mathematically. it could, in theory, be
located in the middle of a park.
Even postcodes unique to one property/business aren't accurate as their
positions are misaligned by the effect of adjacent areas.
which is pity, but that's not a reason not to use the ones that are
available, which is still _far_ more that what we have in the database.
Quantity does not equate to quality.
This may not be a perfect solution but the information CPO/ONSPD
contains is still extremely useful for geocoding. Search for a
postcode and you are _guaranteed_ to get an address in a close
vicinity to a place you are looking for.
No. With an import of the centroids points you're only guaranteed to be
given the location of the node with the postcode.
How about not needing to start Google Maps when searching for a
location on the go?
There's no point in importing to stand alone nodes as deliveries are
destined for buildings. Adding to streets is also pointless for the
same reason plus they can have multiple postcodes.
Addresses on nodes are commonly used in the UK OSM. Many mappers
prefer them over placing addresses on buildings. There are also many
cases (POIs) where nodes are objectively better than buildings. So,
no, there right and wrong solution here.
Allow me to clarify. I should have maybe said 'properties' which can be
represented by nodes instead of 'buildings'.
My objection, which I thought was clear, was to "standalone nodes" with
just a postcode tag.
Besides, the main reason for importing these data is that we can get
_all_ postcodes in the database.
Again quantity /= quality. If you can't manipulate data then it's
useless. These standalone postcode nodes will relate to nothing.
This gives users confidence that when they search for a postcode they
will reliably get a result they are looking for. This is not possible
when merging postcodes with buildings simply because we still have
only a small fraction of buildings in the database.
By the way, I'm not against merging addr:postcode with buildings,
that's exactly what I was doing myself when adding postcodes manually.
However, this is not a process that can be automated (lack of
buildings, single OSM buildings having more than one address/postcode).
Then add buildings.
Based on my experience with mapping postcodes with CPO, I would
recommend starting with an import and merge postcodes and buildings
later.
Experience has shown that doesn't happen. I'm thinking US TIGER imports,
but I'm sure there are other examples.
DaveF
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